1. Field of the Invention
The present invention relates to a recording apparatus for recording images.
2. Description of the Related Art
Japanese Patent Application Laid-open No. H11-130299 discloses a roller pair which moves a recording medium (sheet material) along a guide surface (reference wall) to carry out registration for the recording medium. This roller pair has a transport roller and a skew roller. The transport roller has a rotational shaft orthogonal to the guide surface and transports the recording medium in a transport direction. The skew roller has a cylindrical outer periphery. Further, the skew roller has a rotational shall inclined with respect to the rotational shaft of the transport roller so as to be capable of rotating along with the transport of the recording medium to move the recording medium close to the guide surface. By this configuration, the registration is carried out for the recording medium.
Japanese Patent Application Laid-open No. 2007-161361 discloses a spur skew roller pair which moves a recording medium along a guide surface to carry out registration for the recording medium. The spur skew roller pair disclosed in Japanese Patent Application Laid-open No. 2007-161361 uses a spur instead of the skew roller constituting the roller pair disclosed in the Japanese Patent Application Laid-open No. H11-130299.
Due to the roller pair disclosed in Japanese Patent Application Laid-open No. H11-130299, in the registration for the recording medium, even if an end surface of the recording medium contacts with the guide surface, the recording medium is still moved close to the guide surface by the skew roller. On this occasion, due to the recording medium in contact with the guide surface, a thrust load occurs on the skew roller but, because the recording medium is likely to slip from the skew roller (to move in a direction away from the guide surface), it is possible to restrain the occurrence of a jam of the recording medium. However, if a slip occurs between the skew roller and the recording medium, because the skew roller scrapes images recorded on the recording medium, such a problem that the images are damaged may arise. Further, if the skew roller contacts with the images recorded on the recording medium, such a problem may occur that the recording material for forming the images adheres to the outer periphery of the skew roller and the recording material adhered to the skew roller is transferred to the recording medium to contaminate the recording medium.
On the other hand, if a spur is used instead of the skew roller as in Japanese Patent Application Laid-open No. 2007-161361, because each tooth of the spur has an extremely small contact area with the recording medium in comparison with the skew roller, it is possible to restrain contamination of the recording medium. However, in the registration for the recording medium, because each tooth of the spur pierces the surface of the recording medium as a spike, even if a thrust load occurs on the spur due to the end surface of the recording medium in contact with the guide surface, the recording medium almost does not slip with respect to the spur. As a result, a jam of the recording medium may occur.